Extensive gene mining and facile engineering of a novel carbonyl reductase for asymmetric synthesis of anti-aging (S)-Pro-Xylane from d-xylose

Carbonyl reductases (CRs) are promising biological macromolecules for the asymmetric synthesis of chiral secondary alcohols. A novel CR was evolved for efficient conversion of d -xylose into anti-aging ( S )-Pro-Xylane. Through extensive gene mining, an active carbonyl reductase Zm CR was identified from Zygofabospora marxiana with high reductive activity towards d -xylose-derived 1-C-(β- d -xylopyranosyl)-acetone (XPSA) and in situ cofactor regeneration capability. Using a three-round of concise engineering strategy, a hextuple mutant C85V/V128C/S129A/V161S/Y166H/T217A (M6) was identified from merely 157 mutants with specific activity of 46.00 U·mg −1 , about 306 folds of WT. The Shannon-Wiener index of M6 was 2.21, much higher than WT, indicating its extended substrate scope. M6 could efficiently catalyze the asymmetric reduction of 190 g·L −1 XPSA into ( S )-XPSP. The k cat / K M XPSA of M6 was 203.84 s −1 ·mM −1 , about 910 folds of WT. More non-bonded interactions were monitored in M6, contributing to the stabilization of reactive catalytic conformation. This study provides a promising biocatalyst for the chemoenzymatic synthesis of value-added anti-aging ( S )-Pro-Xylane from lignocellulosic d -xylose.